Single tunnel double bundle posterior cruciate ligament reconstruction

ABSTRACT

The present invention provides a method of performing posterior cruciate ligament replacement. Specifically, a graft tissue is harvested from a patient and single tunnels are prepared in each of the tibia and the femur of the patient. The graft is secured in the femoral tunnel and separated into a posterior cruciate medial bundle and a posterior lateral bundle. The bundles are inserted through the tibial tunnel. During insertion the posterior lateral bundle is positioned in a posterior lateral position in the tibial tunnel while the posterior cruciate medial bundle is positioned in a posterior cruciate medial position in the tibial tunnel. The posterior cruciate medial bundle is then tensioned while the patient&#39;s knee is in approximately 90 degrees of flexion, and the posterior lateral bundle is tensioned while the patient&#39;s knee is approximately in full extension. Each of the bundles is then secured in the tibial tunnel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 61/090,129, which is herein incorporated in its entirety, andis related to U.S. Provisional Patent Application Ser. No. 61/097,460,which is U.S. patent application Ser. No. ______.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention provides a method for posterior cruciate ligamentreconstruction and, more particularly, a method for single tunnel doublebundle posterior cruciate ligament reconstruction.

2. Related Art

Single tunnel single bundle posterior cruciate ligament reconstruction(STSBPCLR) has long been established as a method of posterior cruciateligament (PCL) reconstruction. A variety of graft choices are availableto surgeons during PCL reconstruction. These choices include autogenouspatellar or quadriceps tendon with bone blocks, or hamstring tendons. Inaddition, patellar tendon or achilles tendon allografts (from donors)may be used. The main portion of the PCL which needs to be reconstructedis the anterolateral bundles. Arthroscopic assisted or open PCLreconstructions involve removing the remaining native PCL and drilling atunnel at the anatomic attachment site of the anterolateral bundle atthe anteromedial wall of the itercondylar notch. This tunnel is drilledin line with the roof of the notch and about 6-8 mm from the articularsurface of the lateral femoral condyle. The tibial attachment site isthen prepared by identifying the normal attachment site of the PCL atthe bottom of the PCL facet. A tibial tunnel is drilled, atapproximately a 75° angle and about 6 cm from the joint line, fromposterior to posterior. Once the tunnels are drilled, sharp edges andsoft tissues around the tunnel exit site are smoothed off with the useof a rasp. The graft is then passed into the joint and fixed in itsfemoral tunnel (usually with an interference screw). The graft is thentensioned distally while the knee is cycled several times to remove anyslack in the graft. The graft is fixed to the tibia, usually withstaples, while the knee is flexed to 90°, distal traction is placed onthe graft, and a posterior force is applied to the tibia. Afterfixation, the posterior cruciate drawer is assessed to verify a returnof normal posterior stability to the knee, and the surgical incisionsare closed.

Double bundle double tunnel posterior cruciate ligament reconstruction(DBDTPCLR) has recently been described as a technique for PCLreconstruction which provides two bundles of tissue in separate tunnels.Recent biomechanical studies have shown that an anatomic double-bundlePCL reconstruction is superior in restoring normal knee laxity comparedwith the conventional single-bundle isometric reconstruction. Onetechnique uses a double-bundle Y-shaped hamstring tendon graft. Adouble- or triple-bundle semitendinosus-gracilis tendon graft isutilized and directly fixed with interference screws. In the lateralfemoral condyle, two femoral tunnels are created inside-out through alow anterolateral arthroscopic portal. First, in full extension, thedouble-stranded gracilis graft is fixed with an interference screwinside the lower femoral socket, representing the insertion site of theposteromedial bundle. In 80 degrees of flexion the combinedsemitendinosus-gracilis graft is pretensioned and fixed inside theposterior aspect of the single tibial tunnel. The double- ortriple-stranded semitendinosus tendon is inserted in the higher femoraltunnel, presenting the insertion site of the anterolateral bundle.Finally, pretension is applied to the semitendinosus bundle in fullextension and another screw is inserted. Using this technique, thestronger semitendinosus part of the double-bundle graft, which mimicsthe anterolateral bundle of the PCL, is fixed in full extension, whereasthe smaller gracilis tendon part (posteromedial bundle) is fixed inflexion.

Kinematically the double bundle posterior cruciate ligamentreconstruction has shown itself to be more closely related to the actualnormal motion of the knee when compared to single bundle posteriorcruciate ligament reconstructions. DBDTPCLR is technically demandingprocedure requiring an extremely high level of surgeon skill. Inaddition DBDTPCLR requires four separate fixation devices to secure thesoft tissue bundles in place to recreate a torn posterior cruciateligament. Each bundle of tissue is separately tensioned in therespective tunnel prior to fixation with orthopedic devices.

SUMMARY OF THE INVENTION

The present invention provides a novel technique in which a doublebundle PCL reconstruction is performed through a single tunnel and theseparate bundles are independently tensioned. Accordingly, a new type ofPCL reconstruction the Single Tunnel Double Bundle Posterior CruciateLigament Reconstruction (STBDPCLR) is created.

STDBPCLR utilizes a standard graft harvest and can be performed usingeither allograft or autograft tissues such as bone patellar tendon bone,wherein the graft includes a portion of the patella tendon having a boneplug on each end, or semitendinosus gracilis (hamstring) tendons.Standard tibial and femoral tunnels are prepared using either atrans-tibial or a trans-portal technique. The femoral graft fixation isimportant because the bundles for the PCL must be oriented in a properdirection to provide separate kinematic bundles created a through asingle tunnel. The graft position on the femoral side is held in placethrough screws and/or other fixation devices used where the graft isprepared and separated into two separate bundles through implant designor through surgeon preparation. When using hamstring grafts, the graftsare positioned on the femoral side to provide for a posterior cruciatebundle that can be independently tensioned after femoral tunnelfixation. When using bone patellar tendon bone grafts, the femoral boneplug is left as one piece when inserted and the graft is prepared toprovide for the separate bundles in the tibia.

During graft introduction into the knee two kinematically separatebundles are created. As the graft is pulled into the knee, the surgeon,who has marked the appropriate bundle of tissue which is to be theposterior cruciate lateral bundle, rotates this bundle to the posteriorcruciate lateral position in the tibia while rotating the other bundle,the posterior cruciate medial bundle, to the posterior cruciate medialportion of the tibial tunnel, thereby creating the soft tissue requiredfor both the posterior cruciate lateral and posterior cruciate medialbundles. With the separate bundle created in the knee and appropriatelyoriented, the bundles are tensioned independently. The posteriorcruciate medial bundle is tensioned with the knee in 90 degrees offlexion while the posterior cruciate lateral bundle is tensioned withthe knee in full extension. An external tensioning device is capable ofcycling the separate bundles under tension or this can be accomplishedwith two separate screws inserted as posts into the tibia. Once thegraft is tensioned, tibial fixation is either completed with the screwsalone or, using a removable tensioning device, the bundles are securedin the tibial tunnel with a screw type fixation device and the externaltensioner is removed. By anatomically creating two separate bundles andkinematically tensioning those separate bundles and fixating them, thesurgeon creates a single tunnel double bundle posterior cruciateligament repair (STDBPCLR).

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a view of a graft inserted into the femur of a knee.

FIG. 2 is a view of the graft shown in FIG. 1 separated into twobundles.

FIG. 3 is a view of the two bundles shown in FIG. 2 inserted through thetibia of the knee.

FIG. 4 is a view of the two bundles shown in FIG. 3 arranged as aposterior cruciate lateral bundle and posterior cruciate medial bundle.

FIG. 5 is a view of the knee in extension to provide tension to theposterior cruciate lateral bundle shown in FIG. 4 using a tensioningdevice.

FIG. 6 is a view of the knee in flexion to provide tension to theposterior cruciate medial bundle shown in FIG. 4 using the tensioningdevice shown in FIG. 5.

FIG. 7 is a view of the posterior cruciate lateral bundle and posteriorcruciate medial bundle shown in FIG. 4 secured to the tibia shown inFIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

FIGS. 1-7 illustrate a method of reconstructing the posterior cruciateligament (PCL) of the knee 11 using a single tunnel double bundletechnique. Prior to the reconstruction a standard graft harvest isperformed using either allograft or autograft tissues such as bonepatellar tendon bone or semitendinosus gracilis (hamstring) tendons.Standard tibial and femoral tunnels then are prepared using either atrans-tibial or a trans-portal technique.

As shown in FIG. 1, the graft 10 is fixed in the femur 12 using standardfixation techniques. For example, in the exemplary embodiment, whenusing hamstring grafts, the graft 10 is positioned on the femoral side14 to provide for a posterior cruciate bundle that can be independentlytensioned after femoral tunnel fixation. Alternatively, when using bonepatellar tendon bone grafts, the femoral bone plug is left as one piecewhen inserted and the graft is prepared to provide for the separatebundles in the tibia. The graft is fixed in the femoral tunnel 16 sothat the bundles for the PCL are oriented in a proper direction toprovide separate kinematic bundles created through a single tunnel. Inthe exemplary embodiment, the graft 10 is held in place on the femoralside 14 using screws and/or other fixation devices 17 used when thegraft is prepared and separated into two separate bundles throughimplant design or through surgeon preparation.

As shown in FIG. 2, the graft 10 is separated into two kinematicallyseparate bundles 18 after the graft 10 is introduced into the femur 12.Each bundle 18 is marked as either the posterior cruciate lateral bundle20 or the posterior cruciate medial bundle 22 and pulled through atibial tunnel 24 formed in the tibia 26, as shown in FIG. 3. As shown inFIG. 4, as the graft is pulled through the tibial tunnel 24, the surgeonrotates the bundle labeled posterior cruciate lateral bundle 20 into theposterior cruciate lateral position 28, and rotates the bundle labeledposterior cruciate medial bundle 22 into the posterior cruciate medialposition 30, thereby creating the soft tissue required for both theposterior cruciate lateral bundle 20 and posterior cruciate medialbundle 22.

With the posterior cruciate lateral bundle 20 and the posterior cruciatemedial bundle 22 created in the knee and appropriately oriented, thebundles 20 and 22 are tensioned independently using a tensioning device32 that couples to each bundle 20 and 22. As seen in FIG. 5, theposterior cruciate lateral bundle 20 is tensioned with the knee 11 in afirst position 34 of approximately full extension. As will beappreciated by one of ordinary skill in the art, first position 34 mayinclude a range of extension at or near full extension. Specifically,while in this first position 34, the tensioning device 32 appliestension to the posterior cruciate lateral bundle 20 while the posteriorcruciate medial bundle 22 is left in an untensioned position. As shownin FIG. 6, the knee 11 is then flexed into a second position 36 so thatthere is approximately 90 degrees of flexion between the femur 12 andthe tibia 26. As will be appreciated by one of ordinary skill in theart, second position 36 may include a range of flexion at or near 90degrees. While in this second position 36, the tensioning device 32applies tension to the posterior cruciate medial bundle 22 while theposterior cruciate lateral bundle 20 is left in an untensioned position.In one embodiment, the external tensioning device 32 cycles the separatebundles 20 and 22 under tension as the knee 11 is moved between thefirst position 34 and the second position 36. Alternatively, twoseparate screws are inserted as posts in the tibia 26 to individuallysecure the bundles 20 and 22 so that tensioning of the bundles 20 and 22is performed without the tensioning device 32 by moving the knee 11between the first position 34 and the second position 36.

FIG. 7 illustrates tibial fixation of the posterior cruciate lateralbundle 20 and the posterior cruciate medial bundle 22 with a screw 38.The fixation is performed after the graft 10 has been tensioned andbefore the tensioning device 32 has been removed. In an alternativeembodiment, the tensioning device 32 is used to secure the bundles 20and 22 with any screw type fixation device. In other embodiments,alternative fixation devices may be used to secure the bundles 20 and22. After the bundles 20 and 22 are secured to the tibia 26, thesurgical wound is closed using standard techniques.

Accordingly, the above described invention enables the creation of twoseparate bundles using a single graft that is positioned using a singletunnel. The single tunnel enables a less invasive operation than knownmethods of replacing a posterior cruciate ligament. Moreover, thepresent invention enables the kinematic tensioning of separate bundlesthereby providing a more effective and successful ligament replacement

As various modifications could be made to the exemplary embodiments, asdescribed above with reference to the corresponding illustrations,without departing from the scope of the invention, it is intended thatall matter contained in the foregoing description and shown in theaccompanying drawings shall be interpreted as illustrative rather thanlimiting. Thus, the breadth and scope of the present invention shouldnot be limited by any of the above-described exemplary embodiments, butshould be defined only in accordance with the following claims appendedhereto and their equivalents.

1. A method of replacing a posterior cruciate ligament of a patient,said method comprising: preparing a graft having a first end including afirst bundle and a second bundle and a second end wherein the firstbundle and the second bundle are joined as a single bundle; preparing asingle femoral tunnel in the femur of the patient and a single tibialtunnel in the tibia of the patient; securing the second end of the graftin the femoral tunnel; and securing both the first bundle and the secondbundle of the first end of the graft in the tibial tunnel.
 2. A methodas recited in claim 1, wherein the graft includes a bone patellar tendonbone graft having a femoral bone plug.
 3. A method as recited in claim2, wherein the femoral bone plug is secured in the femoral tunnel andthe graft is prepared to provide for separate bundles in the tibialtunnel.
 4. A method as recited in claim 1, further comprising tensioningthe first and second bundle with a tensioning device coupled to thefirst and second bundle.
 5. A method as recited in claim 1 furthercomprising tensioning the first bundle while the patient's knee is inapproximately 90 degrees of flexion prior to securing the first bundle.6. A method as recited in claim 1 further comprising tensioning thesecond bundle while the patient's knee is approximately in fullextension prior to securing the second bundle.
 7. A method as recited inclaim 1 further comprising positioning the first bundle in a posteriorcruciate lateral position in the tibial tunnel while positioning thesecond bundle in a posterior cruciate medial position in the tibialtunnel prior to tensioning the first and second bundle.
 8. A method asrecited in claim 1, wherein the graft includes a hamstring graft securedto a femur of the patient to provide a bundle that is independentlytensioned after femoral tunnel fixation.
 9. A method of replacing aposterior cruciate ligament, said method comprising: harvesting a grafttissue from a patient; preparing a single tibial tunnel in a tibia ofthe patient and a single femoral tunnel in a femur of the patient;securing the graft in the femoral tunnel; separating the graft into aposterior cruciate medial bundle and a posterior cruciate lateralbundle; inserting the posterior cruciate medial bundle and the posteriorcruciate lateral bundle through the tibial tunnel; positioning theposterior cruciate lateral bundle in a posterior cruciate lateralposition in the tibial tunnel while positioning the posterior cruciatemedial bundle in a posterior cruciate medial position in the tibialtunnel; tensioning the posterior cruciate lateral bundle while thepatient's knee is in approximately 90 degrees of flexion, and tensioningthe posterior cruciate medial bundle while the patient's knee isapproximately in full extension; securing the posterior cruciate medialbundle and the posterior cruciate lateral bundle in the tibial tunnel.10. A method as recited in claim 9, wherein the graft tissue includes ahamstring graft.
 11. A method as recited in claim 10, wherein thehamstring graft is secured to the femur to provide a bundle that isindependently tensioned after femoral tunnel fixation.
 12. A method asrecited in claim 9, wherein the graft tissue includes a bone patellartendon bone graft having a femoral bone plug.
 13. A method as recited inclaim 12, wherein the femoral bone plug is secured in the femoral tunneland the graft is prepared to provide for separate bundles in the tibialtunnel.
 14. A method as recited in claim 9, wherein tensioning theposterior cruciate medial bundle and tensioning the posterior cruciatelateral bundle further comprises tensioning the posterior cruciatemedial bundle the posterior cruciate lateral bundle with a tensioningdevice coupled to the posterior cruciate medial bundle the posteriorcruciate lateral bundle.
 15. A graft for replacing a posterior cruciateligament of a patient, said graft comprising: a first end comprising afirst bundle and a second bundle; a second end wherein the first bundleand the second bundle are joined as a single bundle; a single tibialtunnel formed in the patient's tibia; and a single femoral tunnel formedin the patient's femur, the first bundle and the second bundle of thefirst end configured to secure within the single tibial tunnel, and thesecond end configured to secure within the single femoral tunnel.
 16. Agraft as recited in claim 15, wherein the first bundle is in a posteriorcruciate lateral position in the tibial tunnel.
 17. A graft as recitedin claim 16, wherein the second bundle is in a posterior cruciate medialposition in the tibial tunnel.
 18. A graft as recited in claim 15,wherein the first bundle is tensioned with a tensioning device while thepatient's knee is in approximately 90 degrees of flexion.
 19. A graft asrecited in claim 15, wherein the second bundle is tensioned with atensioning device while the patient's knee is approximately in fullextension.
 20. A graft as recited in claim 15 further comprising a bonepatellar tendon bone graft having a femoral bone plug configured tosecure in the femoral tunnel.